1. Field of the Invention
The invention relates to an analysis device for use in biochemical analytics, with an applicator for decentralized use, containing a first housing, a fluidic system and a sensor module, which together with a second housing forms a measuring and analysis system.
2. Description of the Related Art
One of the requirements for the decentralization of chemical-biological analyses in medical technology is that reagents are flexibly available. In the present context, decentralized means that the analyses are carried out, often not with a high throughput, as in large-scale clinical laboratories. Reagents for chemical-biological analysis are often very costly and greatly restricted in their service life/usability, at least after the container has been opened, for example outgassing of O2 and CO2 from blood-gas calibrating solutions or decomposition of biochemical components, so that efficient, low-cost use is made more difficult or impossible.
Decentralized analyses are therefore carried out particularly advantageously with so-called disposable kits, in which the reagents are provided in a pre-apportioned, individually packed amount required for the specific instance. Known for example is a system (i-STAT Corporation, 303A College Road East, Princeton, N.J. 08540; U.S. Pat. No. 5,096,669) in which a calibrating solution required for the calibration of blood-gas/electrolyte sensors is stored in a gastight aluminum/plastic bag with a content of <1 ml for a disposable sensor and is opened during operation of the disposable sensor by “piercing” the bag wall.
Such a concept of providing calibrating solutions is not suitable for the use of reagents which in dissolved form are subjected to a decomposing process, such as for example enzymes, sensitive organic substances, such as in particular p-aminophenyl-phosphate, p-aminophenyl-β-galactoside. This procedure is also complex and expensive, and there is also the risk of the bags leaking and consequently the entire diagnosis of the blood gas analysis being falsified, for example by escaping gases. Furthermore, in the case of the prior art, only a single calibrating solution is realized and consequently only a one-point calibration is made possible, which casts doubt on the reliability of the results and consequently reduces the acceptance among customers. Although the theoretical possibility of providing more than one calibrating solution is mentioned in U.S. Pat. No. 5,096,669 A, this would increase the complexity, and consequently the production costs, of the disposable article.
Furthermore, the possibility of admixing dry reagents with the sample, i.e. for example the blood sample, is mentioned in U.S. Pat. No. 5,096,669 A. However, this does not solve the problems involved in providing reagents when, for complex diagnostic operations, a number of reagent solutions have to be passed over a sensor device, for example a sensor chip or sensor module, in series before and/or after entry of the sample fluid, for example in the case of analyses with the aid of so-called enzymatic amplification: this involves sequentially feeding in 1. buffer solution, 2. sample, 3. buffer solution, 4. enzyme label reagent, 5. buffer solution, 6. enzyme substrate.
Furthermore, in Dirks, G. et al. “Development of a disposable biosensor chipcard system”, Sens. Technol. Neth., Proc. Dutch Sens. Conf, 3rd (1988), pages 207 to 212, there is a description of a measuring system for biomedical applications in which a so-called chip card is made from a flat container with a number of cavities and a system of fluid channels, with an ISFET which serves as a sensor being introduced into the channel system. In the case of this system, it is in particular a matter of separately feeding a measuring fluid on the one hand and a calibrating or reagent fluid on the other hand to the sensor from separate containers.
Furthermore, in the monograph by Langereis, G.R. “An integrated sensor system for monitoring washing process”, ISBN 90, there is a description of systems with sensors concerned with integrating in fluidic devices sensors which have their signals electrically tapped.